1. Field of the Invention
The invention relates to the field of methods and apparatus for effecting physical examinations. In particular, the invention provides a sensing and feedback device responsive to the position of a patient relative to a nominal examination location, such that the patient is signalled to return to the correct examination location if he or she inadvertently moves away. Preferably, the device is provided in a head support for optical examinations and similar situations that require a relatively accurate and immobile head position, for example for focusing viewing apparatus on the patient's eye.
2. Prior Art
Various physical examinations of patients are common in the medical field for diagnosis, measurement, sensory testing, treatment and the like, and often require the physician to examine a particular area of the patient using a viewer or similar device. An eye examination is a good example that is fairly representative of the field of physical examination. For an eye examination using an optical viewer directed at the patient's eye, a particular relative position must be maintained between the patient's head and the viewing device, such that the viewing device is correctly aimed and focused at the proper focal length needed to view the tissues of interest. Similarly, if the patient is expected to view through a lens configuration or the like, a predetermined position of the patient's head relative to the lens configuration is required.
Ophthalmologists and the like often are equipped with examination devices having a number of alternative devices for viewing, testing and the like. Typically, the patient sits in a chair. A head rest is often provided, on which the patient rests his or her head during the examination. For obtaining a nominal head position, a chin rest and/or forehead rest define reference abutments. For maintaining the nominal position, it is typically the patient's duty to hold his or her head against these abutments. For variations among patients and for effecting different types of tests, the physician has various adjustments for aiming and focus. However, it is undesirable, inconvenient and time consuming for the physician to alter such adjustments during the examination. It is most advantageous if the patient can hold still, with the head comfortably engaged against the chin and/or forehead rests.
Common practice is simply to ask the patient to place his or her head in the proper examination position against the head rest, and to relax and hold still. Whereas typical headrests simply comprise a chin cup and a forehead-stop, the patient has some freedom to move his or her head in the headrest, particularly to the rear. To immobilize his or her head, the examinee (patient) must vigilantly maintain his or her head in the examination position; however, over the course of the examination patients frequently relax and move away from the nominal position, especially retreating from the forehead stop.
Of course the patient can feel the forehead stop and should be aware of his or her head position. Nevertheless, patients very frequently and apparently unknowingly or involuntarily shift away from the examination position. The physician then must ask the patient to move up against the headrest, or must refocus or re-aim the viewing apparatus as necessary. This occurs over and over during the physician's day of examinations, and is a major inconvenience and time waster that unfortunately results from human nature. Despite the best intentions, even the most diligent patient's attention, and his or her head, sometimes wander from correct position on the headrest.
Physicians who conduct eye examinations and the like find themselves perpetually cajoling the patients to resume the examination position. This situation is frustrating to the physician and may be embarrassing to the patient, who generally has the best intentions and is simply inattentive. Alternatives such as placing a strap around the back of the patient's head are unduly intrusive or uncomfortable. It would be desirable to relieve the physician of the role of reminding the patient to remain against the headrest, in a manner that is not unduly burdensome to the patient, and is reasonably polite.